Sure thing! We've got 90663429 and 27443918, and we're going to subtract the second number from the first.

Step 1: We'll start by subtracting the digit 8 and the borrow 0 from 9 in column 1 and get 1.
1 is the first digit of our result.

Step 2: We'll start by subtracting the digit 1 and the borrow 0 from 2 in column 2 and get 1.
1 is the next digit of our result.

Step 3: We'll start by subtracting the digit 9 and the borrow 0 from 4 in column 3 and get -5.
We add -5 to 10 and get 5 as the next digit of the result.

Step 4: We'll start by subtracting the digit 3 and the borrow 1 from 3 in column 4 and get -1.
We add -1 to 10 and get 9 as the next digit of the result.

Step 5: We'll start by subtracting the digit 4 and the borrow 1 from 6 in column 5 and get 1.
1 is the next digit of our result.

Step 6: We'll start by subtracting the digit 4 and the borrow 0 from 6 in column 6 and get 2.
2 is the next digit of our result.

Step 7: We'll start by subtracting the digit 7 and the borrow 0 from 0 in column 7 and get -7.
We add -7 to 10 and get 3 as the next digit of the result.

Step 8: We'll start by subtracting the digit 2 and the borrow 1 from 9 in column 8 and get 6.
6 is the next digit of our result.

So, 90663429 - 27443918 = 63219511.